What is the minimum number of lines to separate the sets?

[![enter image description here][1]][1]


Observe the graph below, it is possible to separate linearly with a line at least two of the classes?




[![enter image description here][3]][3]

How many circles are needed to group all points into three groups with 2
points and a group with 4 points?

[![enter image description here][2]][2]

I believe the answers are

 1. 5
 2. is not possible
 3. there will always be points left over

These challenges were proposed to me by a discreet math teacher and, as they are "challenges", I don't imagine that the answers are so simple.

[Source](https://www.amazon.com.br/Visual-Split-Puzzles-English-Kevin-ebook/dp/B08NYWW5VG/ref=sr_1_1__mk_pt_BR=%C3%85M%C3%85%C5%BD%C3%95%C3%91&dchild=1&keywords=visual+puzzle&qid=1609466327&sr=8-1)
  
[1]: https://i.sstatic.net/Xgwhi.png
  [2]: https://i.sstatic.net/QVhV4.png
  [3]: https://i.sstatic.net/5hyHS.png